1. Field of the Invention
The present invention relates to an apparatus and method for the generation and safe delivery of disinfected, therapeutic vapor. More specifically, the present invention provides a vaporizer device and vaporization method for the flash boiling of small volumes of aqueous liquid to heated vapor in a safe and energy-efficient manner using a lightweight, compact and portable personal vaporization device.
2. Discussion of the Related Art
One class of devices that can be used to generated vapor from liquid at room temperature is known in the art as capillary pumps, capillary vaporization modules or capillary force vaporizers. These devices generate pressurized vapor directly from unpressurized liquid by applying heat to cause liquid to boil within a capillary member, and by at least partially constraining the evolved vapor to allow pressure to increase, and then exit the device through one or more orifices as a high velocity jet. Such devices are thermally powered, compact, and generally have no moving parts, thereby offering certain advantages over other techniques used for liquid vaporization and vapor pressurization. Capillary force vaporizers and devices in which they may be found are variously described in U.S. Pat. Nos. 5,692,095; 5,870,525; 6,162,046; 6,347,936; 6,585,509 and 6,634,864.
For decades, the vaporization of liquids for humidification purposes has been recommended by physicians for a wide range of medical conditions. Consumers have also found humidification useful and beneficial for various aspects of personal care. Physicians regard humidification as part of “supportive care,” that is, any intervention that helps to relieve symptoms and provide comfort to a patient in addition to rest, fever control, and hydration. Consumers have used humidification for purposes such as skin moisturization and as an aid in cleansing.
As the popularity of humidification sources in the form of room humidifiers rose towards the latter part of the 20th century, however, humidifier-related problems surfaced. According to medical literature, for example, the use of room humidifiers can lead to an increase in the presence of allergens related to mold and dust mites, as humidifiers can promote the growth of such organisms in a room. Moreover, thermal injuries have been associated with the use of warm mist room humidifiers when abundant volumes of hot or boiling water are inadvertently spilled on a patient during humidifier use or during the time required to heat water. Cool mist room humidifiers, on the other hand, are prone to bacterial growth in their water reservoirs and can propagate microbes during dispersion. This has lead to reports of various flu-like symptoms in some patients, which have been collectively termed “humidifier fever.” Examples of cool mist humidifiers include: ultrasonic humidifiers, which produce a cool mist using ultrasonic vibrations; impeller humidifiers, which produce a cool mist with a rotating disk; and evaporators, which variously use a fan to blow air through a wet wick, filter or belt.
In addition to the foregoing problems, most prior art humidifiers require some passage of time for their liquid reservoirs to be heated to a high enough temperature to be able to provide desired vapor. Even those vaporizers that employ a liquid supply in lieu of a reservoir are not able to generate vapor instantaneously. Moreover, most prior art vaporizers do not protect against hazards due to inadvertent scalding. U.S. Pat. Nos. 4,532,088 and 4,657,713 both to Miller, K. G., for instance, teach a humidifier assembly comprising a housing, a horizontally disposed heater, a liquid water supply means, a humidification chamber with an inlet for a breathable gas and an outlet for humidified breathable gas, and a hydrophobic filter. Neither of these patents teaches a method of providing nearly instantaneous water vapor or the avoidance of scalding hazards.
U.S. Pub. No. 20090145847A1 to Spiegelman, et al., teaches methods and systems for the purification of steam that can be operated at either relatively high or relatively low operating temperatures and under sub-atmospheric pressures. However, neither the generation of nearly instantaneous, directed water vapor nor the denaturing or killing of microbes, or avoidance of scalding hazards are addressed. U.S. Pat. No. 6,367,472 to Koch describes a respiration humidifier comprising an outer jacket, a plurality of semi-permeable hydrophobic hollow fibers, a water feed, a breathing feed line and a breathing gas drain line in flow connection with an interior of the hollow fibers, and an electrical heating means for electrically heating the hollow fibers. In order to deliver the necessary heat of evaporation, however, this unit requires 60 W of power, which is equivalent to 3.6 kJ/min or more than 100 kJ over the course of 30 minutes. U.S. Pat. Nos. 6,102,037 and 6,718,973, also to Koch, describe a metering device, and an evaporation chamber for mixing, respectively, but do not describe a heating means, and thus the means for generating water vapor water.
EP2072471 to Nomura, et al., teaches a sterilization method for water that involves applying a high voltage pulse to a pair of discharge electrodes comprising a high voltage electrode and a ground electrode in the water, so that dielectric breakdown occurs and bubbles are generated in the water to cause a jet. This patent does not teach nearly instantaneous delivery of directed or pressured heated water vapor, nor the denaturing or killing of microbes. U.S. Pat. No. 3,695,267 to Hirtz, et al., teaches a tubular device for personal use, however, the tubular portion of the device must be water cooled in order to avoid potential scalding to the user. Miller, in U.S. Pat. No. 4,532,088, teaches a vented humidification space for receiving vapor passed through a hydrophobic filter mounted on a heater through which water flows. The heater requires a ball valve, however, to prevent the delivery of water to the heater if the filter is not in place.
In light of the foregoing, it would be advantageous to provide a technique for vaporization that is free from scalding hazards and that additionally does not support the transmission of microbes, bacteria or molds. In addition, it is desirable to provide a device that can provide therapeutic warmth without requiring the heating of large quantities of water. It would be also desirable to permit the generation of water or aqueous vapor in as short a time as possible, especially if that could be accomplished in an energy-efficient manner.